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Unit testing importance and benefits

One of the best ways to ensure that developed code, methods, or functions behave as they should is through unit tests. Today, we explain unit testing, its importance, and its benefits in the software development process.

Unit testing is a testing technique that allows you to isolate each unit to identify, analyze, and fix defects. Moreover, it allows the developer to ensure that the code works after changes to the code base.

What is unit testing?

In computer science, unit testing is the verification that individual code units such as functions or portions of code are complying with the desired ends.

Unlike general testing, where the main general functionalities are verified, in the unit testing, each part of the individual components of the software is reviewed in detail to optimize the error identification process.

The main objective is to test small parts of the code to identify bugs and prevent them from returning.

The process is executed during the development of an application by the developers. These tests are regularly included in a pipeline that has the job of running them and only accepts new code if its tests run successfully.

Unit testing is a white box testing technique, a method of software testing that verifies internal structures or workings of an application, as opposed to its functionality.

In general, it can be said that it applies a divide and conquer technique, whereas the tests are made to fragmented parts of the code, it becomes easier to identify root error causes.

Importance of unit testing

Executed in early development, as in test-driven development, unit testing saves time and money because developers can find problems before coding begins.

The cost of repairing errors in an early stage is considerably lower than the cost of detecting, identifying, and correcting the bug later. Plus, this type of verification is different and more efficient than the informal tests that developers usually do on a day-to-day basis.

Also, by doing that, the developer gains productivity, prevents future problems, assures good quality software, and improves all aspects of the code. Well-executed unit tests also serve as project documentation.

Benefits of unit testing

As mentioned above, the unit tests isolate small parts of the software code and show if it meets its behaviors as intended. These are some of the benefits of using this testing technique:

  • Unit tests can provide a basic understanding of the unit API.
  • Unit testing allows the programmer to refactor code and assure the module is still working correctly. 
  • Due to the modular nature of the unit testing, we can test parts of the project without waiting for others to be complete.
  • Unit testing allows the programmer to refine code and ensure the module works properly.
  • Unit tests can be used as documentation. Each test should be able to clearly explain the expected output for a given input. In addition, it should be able to verify that it actually works.


Keep in mind that unit tests can’t catch every error in the program once it only tests the functionality of the units alone. 

Therefore, it will not catch integration errors or broader system-level errors. Unit tests should be executed in conjunction with other software testing activities.

Unit testing also demands discipline throughout the software development process. It is essential to keep meticulous records of the tests performed and the changes made to the source code of this or any other unit in the software. 

Unit testing best practices

Start by doing tests on the impact of the behavior of the entire system. The bug will reappear if not appropriately corrected. 

Unit tests should take very little time to run because mature projects normally have thousands of tests. So, try not to introduce dependencies on infrastructure when writing unit tests because they make them run slowlier.

Also, write test cases to ensure the performance of the code. Remember that unit test cases should be independent. 

Accordingly to Microsoft, among other practices, you should:

  • Name your tests because they explicitly express the intent of the test.
  • Arranging your tests because it clearly separates what is being tested from the arranging and assert steps.
  • Write minimally passing tests once they become more resilient to future changes in the codebase.


As explained, unit testing can be fundamental to developers. Is it a type of error checking that stands out because it is efficient, simple, and supports future maintenance!

Unit testing accelerates workflow while also saving time and money. It also can be used as a documentation base which can be fundamental to involve new people in the project and maintain consistency, clarity, and good results for the team and the company.

At Zalox, we can help you achieve a well-developed project, tested in every way to prevent errors and bugs. Talk to us!

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